per la fine del corso abbiamo fatto un sito.
vi spiego la struttura: c'è un index.php e vari file php che contengono le varie funzioni.
tutte vengono richiamate nel div content quando si clicca su un link.
vi posto il codice:
Codice PHP:
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">

<html>

    <head>

        <title>Farmacia Online</title>

        <meta http-equiv="Content-Type" content="text/html;charset=windows-1250">

        <meta name="author" content="Yoursite.com">

        <meta name="copyright" content="Yoursite.com">

        <meta name="description" content="YourSite">

        <meta name="keywords" content="">

        <link rel="stylesheet" type="text/css" href="css/style.css">

    </head>

    <body>

        <div id="container">

            <div id="top">

                [b]Prozac Club![/b]

                <span class="podnaslov">


        Acquista i peggiori prodotti sul mercato!!

                </span>

                <div id="logo">[img]images/logo.gif[/img]</div>

                <div id="banner">[img]images/spinello2.gif[/img]</div>

            </div>

            <div id="left">

                [url="index.php"]Home[/url]

                [url="index.php?car=1"]Prodotti[/url]

                [url="index.php?car=4"]Commenta[/url]

                [url="index.php?car=3"]Contatti[/url]

                




                <?php

                
include ("Config.php");

                
$link mysql_connect($host$user$password) or die("Non è possibile connettersi al database");

                
$c mysql_select_db($db$link) or die("Non è possibile selezionare il database");

                @
session_start();

                if (isset(
$_POST['login'])) {

                    
$u $_POST['username'];

                    
$p $_POST['password'];

                    
$query "select*from utenti where user = '$u'";

                    
$result mysql_query($query$link) or die(mysql_error($link));

                    
$riga mysql_fetch_row($result);

                    if (
$riga[0] == "") {

                        echo 
'<script language="javascript">document.location.href="' $destinazione '"</script>';

                    } else {

                        if (
$riga[2] == $p) {

                            
session_register('Autorizzato');

                            
$_SESSION["Autorizzato"] = $u;


                        } else {

                            echo 
'<script language="javascript">document.location.href="' $destinazione '"</script>';

                        }

                    }

'"</script>';

                }

                
?>



                <?php

                
if (!session_is_registered('Autorizzato')) {

                
?>

                    <form name="formlogin" method="post" action="#" >

                        



                            Username: 
<input name="username" type="text" size="16">


                            Password: 
<input name="password" type="password" size="16">



                            <input name="login" type="submit" class="login" value="Login">

                            <input type="button" class="login" onclick="document.location.href='registrazione.php';" value="Registrazione">

                        </p>

                    </form>

                <?php

                
} else {

//                    echo "Benvenuto " . $_COOKIE['utente'] . "

";

                    echo "
Benvenuto " . $_SESSION['Autorizzato'] . "

";

                ?>

                    <form name="
formlogout" method="post" action="destroy.php">

                        



                            <input name="
logout" type="submit" class="login" value="Logout">

                        </p>

                    </form>

                <?php

                }

                ?>

                




            </div>

            <div id="
right">

                <script type="
text/javascript">



                    // Google Internal Site Search script II- By JavaScriptKit.com ([url]http://www.javascriptkit.com[/url])

                    // For this and over 400+ free scripts, visit JavaScript Kit- [url]http://www.javascriptkit.com/[/url]

                    // This notice must stay intact for use



                    function Gsitesearch(curobj){

                        var domainroot="
http://localhost/sitofinale/ "

                        
curobj.q.value="site:"+domainroot+" "+curobj.qfront.value

                    
}



                
</script>



                <form action="http://www.google.com/search" method="get" onSubmit="Gsitesearch(this)">



                    



                        <input name="q" type="hidden" />

                        <input name="qfront" type="text" style="width: 140px" /> 

                        <input type="submit" value="Cerca" class="submit" />


                    </p>



                </form>

                <h3>Acquista</h3>

                [url="index.php?car=2"][img]images/carrello.gif[/img][/url]



                <?php

                
@$carrello $_SESSION['carrello'];

                if (!
$carrello) {

                    echo 
"Il carrello e' vuoto.
"
;

                } else {

                    
$prodotti = @explode(','$carrello);



                    echo 
'Ci sono [url="index.php?car=2"]' . @count($prodotti) . ' prodotti nel carrello.[/url]
'
;

                }

                
?>

            </div>

            <div id="content">





<?php

                
if (!isset($_GET['car'])) {

                    echo 
'<h2 id="wel">Welcome</h2>';

?>

                

Per aprire la pagina di amministratore andate su[url="admin/index.php"]Admin[/url].I dati di login sono: admin admin</p>



<?php

                
}

                if (
$_GET['car'] == 1) {

                    echo 
'<h2 id="wel">Prodotti</h2>';

                    include (
"indexcar.php");

                }

                if (
$_GET['car'] == 2) {

                    echo 
'<h2 id="wel">Carrello della spesa</h2>';

                    include (
"carrello.php");

                }

                if (
$_GET['car'] == 3) {

                    echo 
'<h2 id="wel">Contatti</h2>';

                    include (
"contatti.php");

                }

                if (
$_GET['car'] == 4){

                    echo 
'<h2 id="wel">Commenti</h2>';

                    include (
"visualizza.php");

                }

?> 

            </div>

            <div id='footer'>

               
            </div>

        </div>

    </body>

</html>
rispetto a quello che mi avete spiegato com'è?